Vehicle detector unit, vehicle detector system and a method for detecting presence of a vehicle on a rail

ABSTRACT

A vehicle detector unit for detecting presence of a vehicle moving along a rail, including a distance sensor for sensing a body of the vehicle, a rail translation sensor for sensing translation of the rail, a rail torsion sensor for sensing torsion of the rail, and a processor adapted to process data received from the distance sensor, the rail translation sensor and the rail torsion sensor, whereby the processor applies an algorithm to said data to determine whether to output an alert signal.

FIELD OF THE INVENTION

The invention relates to a vehicle detector unit, a vehicle detectorsystem and a method for detecting presence of a vehicle on a rail. Moreparticularly, but not exclusively, the invention relates to a vehicledetector unit for detecting presence of a train on a rail for providingan alert to a worksite.

BACKGROUND OF THE INVENTION

It is known to provide a railroad warning system for train operators. Inparticular, U.S. Pat. No. 8,109,474 discloses a dual ultrasonic traindetector for giving train workers, railroad personnel and others warningof oncoming trains.

The applicant has identified that existing train detector systems areprone to unreliability, faulty detection of threat, and possible failureto identify threats in certain circumstances. Examples of the presentinvention seek to provide an improved train detection system whichovercomes or at least alleviates disadvantages associated with existingsystems.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a vehicledetector unit for detecting presence of a vehicle moving along a rail,including a distance sensor for sensing a body of the vehicle, a railtranslation sensor for sensing translation of the rail, a rail torsionsensor for sensing torsion of the rail, and a processor adapted toprocess data received from the distance sensor, the rail translationsensor and the rail torsion sensor, whereby the processor applies analgorithm to said data to determine whether to output an alert signal.

Preferably, the processor applies said algorithm to detect uncorrelateddata received from the distance sensor, the rail translation sensor andthe rail torsion, sensor to distinguish between a dangerous event, inwhich case the vehicle detector unit outputs an alert signal, and anon-dangerous event, whereby the processor identifies a non-dangerousevent in response to detecting uncorrelated data and the processoridentifies a dangerous event in response to detecting correlated data.

Preferably, the processor is arranged to detect possible degradation ofoperation of the vehicle detector unit when greater than a predeterminedthreshold of non-dangerous events are detected within a predeterminedperiod and in the absence of detecting a dangerous event. Morepreferably, the vehicle detector unit outputs an error signal inresponse to detecting possible degradation of operation of the vehicledetector unit.

In a preferred form, the processor is arranged to detect correlated datawhen there is consistency between data received from the distancesensor, the rail translation sensor and the rail torsion sensor toindicate presence of a vehicle moving along the rail, based on thresholdvalues for each of the sensors. More preferably, the processor isarranged to detect, correlated data for fast short vehicles and slowlong vehicles on the rail, and to detect uncorrelated data forwind-blown debris, dust, rain and the like.

Preferably, the processor is arranged to distinguish presence ofvehicles on adjacent tracks from presence of vehicles on said rail.

Preferably, the distance sensor is in the form of an ultrasonic sensor.

Preferably, the rail translation sensor is in the form of anaccelerometer.

Preferably, the rail torsion sensor is in the form of a gyroscopicsensor.

In a preferred form, the vehicle detector unit includes base for passingbeneath said rail a first clamp which is fixed relative to the base forclamping one side of the rail, and a second clamp which is selectivelymovable relative to the base for clamping an opposite side of the rail.More preferably, the second clamp is selectively held in place relativeto the base by operation of a releasable fastener.

In accordance with another aspect of the present invention, there isprovided a vehicle detector system for detecting presence of a vehiclemoving along a rail relative to a work site, said system including apair of vehicle detector units at spaced locations along the rail, afirst one of the vehicle detector units being located in one directionfrom the work site and a second one of the vehicle detector units beinglocated in an opposite direction from the work site, each of the vehicledetector units being a vehicle detector unit as claimed in claim 1, saidsystem further including a site warning unit located at the work site,wherein the site warning unit is in communication with the vehicledetector units, and the site warning unit outputs audible and/or visualalerts in response to an alert signal received from either of thevehicle detector units.

Preferably, the site warning unit is in communication with the vehicledetector units by way of radio communication.

In accordance with another aspect of the present invention, there isprovided a method for detecting presence of a vehicle on a rail, saidmethod including the steps of:

-   -   using a distance sensor for sensing a body of the vehicle,    -   using a rail translation sensor for sensing translation of the        rail.    -   using a rail torsion sensor for sensing torsion of the rail, and    -   processing data received from the distance sensor, the rail        translation sensor and the rail torsion sensor, whereby an        algorithm is applied to said data to determine whether to output        an alert signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described, by way of non-limiting example only, withreference to the accompanying drawings, in which:

FIG. 1a shows a side view of a vehicle detector unit in accordance withan example of the present invention;

FIG. 1a shows a bottom perspective view of the vehicle detector unit;

FIG. 2 shows a detailed transparent view of one end of the vehicledetector unit;

FIG. 3 is a diagrammatic representation of an algorithm used by avehicle detector unit;

FIG. 4 is a diagrammatic view of a vehicle detector system in accordancewith an example of the present invention;

FIG. 5 is a diagrammatic representation of hardware architecture of arepeater unit of the vehicle detector system;

FIG. 6 is a diagrammatic representation of a procedure followed by thevehicle detector system;

FIG. 7 is a diagrammatic representation of the vehicle detector systemwhen installed to provide warning to worksite;

FIG. 8 shows a detailed side view of a vehicle detector unit inaccordance with an example of the present invention, depicting clamps ofthe vehicle detector unit;

FIG. 9 shows a side view of a vehicle detector unit in accordance withthe example shown in FIG. 8; and

FIG. 10 shows a partial sectional side view of one end of the vehicledetector unit shown in FIG. 9.

DETAILED DESCRIPTION

With reference to FIGS. 1a to 3 of the drawings, there is shown avehicle detector system which is able to provide warning to a worksiteof a train (or other vehicle) approaching the worksite along a rail.Advantageously, as the vehicle detector unit includes a distance sensor,a rail translation sensor, a rail torsion sensor and a processor, thevehicle detector unit is able to combine data received from thedifferent sensors so as to achieve an improved level of reliability,particularly in detecting dangerous events and in avoiding beingtriggered by false triggers.

More specifically. FIGS. 1a to 3 depict a vehicle detector unit 10 fordetecting presence of a vehicle moving along a rail 12, including adistance sensor 14 for sensing a body of the vehicle, a rail translationsensor 16 for sensing translation of the rail 12, and a rail torsionsensor 18 for sensing torsion of the rail 12. The vehicle detector unit10 also includes a processor adapted to process data received from thedistance sensor 14, the rail translation sensor 16 and the rail torsionsensor 18, whereby the processor applies an algorithm to the data todetermine whether to output an alert signal. The alert signal can betransmitted to produce an audible and/or visual alert to a worksitewhich is remote to the vehicle detector unit 10, as depicted in thevehicle detector system shown in FIGS. 4 to 7.

The processor may be located within a housing 20 of the vehicle detectorunit. The processor applies the algorithm to detect uncorrelated datareceived from the distance sensor 14, the rail translation sensor 16 andthe rail torsion sensor 18 to distinguish between a dangerous event, inwhich case the vehicle detector unit 10 outputs an alert signal, and anon-dangerous event, in which case the vehicle detector unit 10 does notoutput an alert signal. The processor identifies a non-dangerous eventin response to detecting, uncorrelated data, and the processoridentifies a dangerous event in response to detecting correlated data.This processing of data is performed by combining data from the distancesensor 14. the translation sensor 16 and the rail torsion sensor 18 in amanner which is depicted by the flow chart in FIG. 3. Provided theprocessor recognises criteria according to the algorithm wherein datafrom the sensors is correlated to indicate presence of a vehicle movingalong the rail 12. an alert signal is provided as an output of thevehicle detector unit 10.

The processor may be arranged to detect possible degradation ofoperation of the vehicle detector unit 10 when greater than apredetermined threshold of non-dangerous events are detected within apredetermined period and in the absence of detecting a dangerous event.In this case. the vehicle detector unit 10 may output an error signal inresponse to detecting possible degradation of operation of the vehicledetector unit. This may indicate that the system may be unable tooperate correctly. The system may use an alternative signal to indicate,that the system may be unable to function. For example, the system mayuse an alert sound from repeater units and site warning units to warnoperators that the system may be unable to function and that the systemmay be less reliable.

The processor may be arranged to detect correlated data when there isconsistency between data received from the distance sensor 14, the railtranslation sensor 16 and the rail torsion sensor 18 to indicatepresence of a vehicle moving along rail, based on threshold values foreach of the sensors 14, 16, 18. The processor may be arranged to collectcorrelated data for fast short vehicles and slow long vehicles on therail 12. and to detect uncorrelated data for wind-blown, debris, dust,rain and the like. The processor may be arranged to distinguish presenceof vehicles on adjacent tracks from presence of vehicles on the rail 12.

The distance sensor 14 may be in the form of an ultrasonic sensor, therail translation sensor 16 may be in the form of an accelerometer, andthe rail torsion sensor 18 may be in the form of a gyroscopic sensor.

Advantageously, the applicant has been able to apply a combination ofmicroelectronic sensors and signal processing in a novel, fashion toreliably detect approaching trains. The vehicle detector unit 10incorporates microelectronics, complex signal processing, and radiocommunications technology. Ultrasonic sensing technology combined withprecision measurement of rail translation and rail torsion providesfiltering that, when combined, provide a level of reliability that issuperior to existing vehicle protection products. In particular,improved system reliability is achieved via combined monitoring ofvehicular presence by way of combining a distance sensor with railtranslation and rail torsion sensors. Although it has previously beenproposed in an existing system to use only an ultrasonic sensor, thepresence of a vehicle which is relatively small (for example, a 3 metrelength vehicle as opposed to a 100 metre length train) may appearsimilar to an animal running past, at least to an ultrasonic sensor inisolation. Accordingly, if a mere ultrasonic sensor system is programmedto avoid false triggering based on a running animal, that system mayalso miss the threat provided by such a relatively small vehicle.Advantageously, by virtue of the sensor fusion of the present invention,such threats and false triggers are accommodated. Previously, falsetriggers of this kind may have been dealt with by simply removing shortpulses, however this would effectively limit the maximum speed at whichthe existing system would detect vehicles (in particular relativelyshort vehicles or “high-rail” vehicles).

Advantageously, the present invention uses an algorithm which combinesdata collected on the ultrasonic sensor, accelerometer and gyroscope tomanage scenarios including but not limited to fast short vehicles, longslow vehicles and vehicles on adjacent tracks.

In relation to the algorithm, digital signal filtering and temporalsynchronisation are used for the Accelerometer, Gyroscope and Ultrasonicsensors. Ultrasonic sensor phenomena unrelated to vehicle detection, asdefined by duration, distance thresholds and correlation with othersensors, is implemented such that these phenomena are removed to thereduce effect on digital signal filtering in following stages. If manyphenomena are removed in a short time, a degraded system signal istriggered.

The ultrasonic sensor is used such that a threshold and minimum timeperiod are required to trigger an alarm. The time period is shortened ifa detection trigger is present from MEMS sensors.

A MEMS trigger is determined primarily by a threshold on the ratio ofRMS power in short and long terms whereby the long term period followsthe short term period. A MEMS trigger is continued while the long termRMS power remains above a threshold. The MEMS trigger is finallycontinued by way of a fixed period after the aforementioned triggers.Thresholds and timers vary between gyroscopic and accelerometricsensors.

Accordingly, examples of the present invention use a distance sensor incombination with torsion and translation sensors, using analoguedistance, which is useful for defining thresholds and determiningbetween rain and trains, rather than simple digital (on/off) “presence”.The present invention uses soundwaves from the ultrasonic sensor todetermine distance to the train. No electric or physical connection ismade to the train or components of the train. There is no electrical ormechanical interface interfering with the train or the rail. Sensorfusion as implemented in the present invention enables the vehicledetector unit 10 to differentiate trains, track equipment, environmentaleffects, debris, electrically and mechanically induced noise, theadjacent track, and other factors. This improvement in differentiationsignificantly improves the reliability of detection and incidences offalse detection.

The vehicle detector unit 10 may include a base 22 for passing beneaththe rail, a first clamp 24 which is fixed relative to the base 22 forclamping one side of the rail 12, and a second clamp 26 which isselectively movable relative to the base 22 for clamping an oppositeside of the rail 12 (see FIG. 1A and FIG. 1B). The second clamp 26 maybe selectively held in place relative to the base 22 by operation of areleasable fastener 28 which can be in the form of a threaded base and awing nut. As the second clamp 26 is able to be slid on and locked to thebase 22 by a single wing nut, this makes for very fast attachment andreduces the time spent by an operator on the track in the danger zone.The profile of the base 22 allows for easy installation with minimaldisruption to ballast (rock) from under the foot of the rail 12 duringinstallation. Accordingly, examples of the present invention may bequick to install and may support multiple rail standard sections.Accordingly, the vehicle detector unit 10 may be readily installedtemporarily when work is to be undertaken at a worksite at or near asection of the rail 12.

With reference to FIGS. 4 to 7, one aspect of the present inventionprovides a vehicle detector system 30 for detecting presence of avehicle moving along a rail 12 relative to a worksite 32. The system 30includes a pair of vehicle detector units 10 at spaced locations alongthe rail 12, a first one of the vehicle detector units 10 being locatedin one direction from the worksite 32 and a second one of the vehicledetector units 10 being located in an opposite direction from theworksite 32. The first vehicle detector unit 10 is for detecting trainsincoming to the worksite 32 while the second one of the vehicle detectorunits 10 is for detecting trains leaving the worksite such that they donot initiate an alarm. In an alternative example, there may be more thanone vehicle detector unit 10 located at each side of the worksite 32 fordetecting incoming velocity of trains. Each of the vehicle detectorunits 10 may he a vehicle detector unit 10 as shown in FIGS. 1a to 3 andas described above.

The system 30 further includes a site warning unit 34 located at theworksite 32. The site warning unit 34 is in communication with thevehicle detector units 10 and the site warning unit 34 outputs audibleand/or visual alerts in response to an alert signal received from eitherof the vehicle detector units 10.

The site warning unit 34 may he in communication with the vehicledetector units 10 by way of radio communication. Alternatives includessatellite, cellular and wired communication. Satellite has ongoing costsand is unreliable. Cellular is not available in the normal areas ofdeployment. Although inherently more reliable than wireless, wiredconnections require long lengths of wires and need to be run under thetracks. This increases installation time and equipment weightsignificantly. In addition, long installation times prevent use ofsafety systems during short track occupations where the risk to workersmay be very high. Radio communication certification is related to outputpower (effective isotropic radiated power). To achieve acceptable rangethrough radiofrequency opaque objects in the Frenel zone, highsensitivity receivers are required. Range is related to elevation so asthe train detectors are low on the track, and repeater units (used closeto the train detectors) are on tripods.

More specifically, with reference to FIG. 4, the system 30 may include aplurality of repeater units 36 which have sirens and lights on a tripodwith an additional long distance radio. Hardware architecture of therepeater units 36 is shown in FIG. 5.

The site warning units 34 may each include a siren and lights on atripod. The vehicle detector system 30 may also include personal warningunits 38 which may be clipped onto a belt by workers, and lookout units40 which may be held by a lookout person.

FIG. 6 shows a series of steps in a flowchart which may be followed byexamples of the vehicle detector system 30, and FIG. 7 shows adiagrammatic view where vehicle detector units 10 are installed at adistance of 1.5 km at either side of the worksite 37.

FIGS. 8 to 10 depict a vehicle detector unit 10 in accordance with afurther example of the present invention. The vehicle detector unit 10shown in FIGS. 8 to 10 is generally similar to the one shown in FIGS. 1ato 7, and like features are denoted with like reference numerals.

The vehicle detector unit 10 of FIGS. 8 to 10 differs in that itincludes a cam 42 for operating the second clamp 26 in place of the nut(or wing nut) used in the example shown in FIG. 1a . The vehicledetector unit 10 of FIGS. 8 to 10 also differs in that it includes heatshielding 44 to protect the housing 20 and the processor within thehousing 20.

More specifically, with reference to FIG. 8, the cam 42 is operated byway of a lever 46, and may be configured for quick operation such thatthe cam 42 is able to be operated to engage/disengage the clamp 26against the rail 12 by less than a single full turn of the lever 46. Asshown in FIG. 9, the first and second clamps 24, 26 are able toaccommodate rails 12 of different profiles—rails of different profileshave been superimposed in FIG. 9 to illustrate this aspect.

Turning to FIG. 10, heat shielding 44 is provided below the housing 20to protect from heat the housing 20 and the processor within the housing20. The applicant has determined that at locations where the vehicledetector unit 10 is to be used there may be damaging heat not only fromdirect sunlight but also in the form of radiation from “ballast” rocksbeneath or adjacent the rails, with the rocks acting in a similar mannerto coals of a barbecue. The heat shielding 44 may be in the form of asled mounted to an underside of the vehicle detector unit 10 with an airgap between the heat shielding 44 and the vehicle detector unit 10 alonga substantial portion of a length of the sled as shown in FIG. 10 so asto insulate the vehicle detector unit 10.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not by way of limitation. It will be apparent to aperson skilled in the relevant art that various changes in form anddetail can be made therein without departing from the spirit and scopeof the invention. Thus, the present invention should not be limited byany of the above described exemplary embodiments.

The reference in this specification to any prior publication (orinformation derived from it), or to any matter which is known, is not,and should not be taken as an acknowledgment or admission or any form ofsuggestion that that prior publication (or information derived from it)or known matter forms part of the common general knowledge in the fieldof endeavour to which this specification relates.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising”, will be understood to imply the inclusionof a stated integer or step or group of integers or steps but not theexclusion of any other integer or step or group of integers or steps.

1. A vehicle detector unit for detecting presence of a vehicle movingalong a rail, including a distance sensor for sensing a body of thevehicle, a rail translation sensor for sensing translation of the rail,a rail torsion sensor for sensing torsion of the rail, and a processoradapted to process data received from the distance sensor, the railtranslation sensor and the rail torsion sensor, whereby the processorapplies an algorithm to said data to determine whether to output analert signal.
 2. A vehicle detector unit as claimed in claim 1, whereinthe processor applies said algorithm to detect uncorrelated datareceived from the distance sensor, the rail translation sensor and therail torsion sensor to distinguish between a dangerous event, in whichcase the vehicle detector unit outputs an alert signal, and anon-dangerous event, whereby the processor identifies a non-dangerousevent in response to detecting uncorrelated data, and the processoridentifies a dangerous event in response to detecting correlated data.3. A vehicle detector unit as claimed in claim 1 , wherein the processoris arranged to detect possible degradation of operation of the vehicledetector unit when greater than a predetermined threshold ofnon-dangerous events are detected within a predetermined period and theabsence of detecting a dangerous event.
 4. A vehicle detector unit asclaimed in claim 3, wherein the vehicle detector unit outputs an errorsignal in response to detecting possible degradation of operation of thevehicle detector unit.
 5. A vehicle detector unit as claimed in claim 2,wherein the processor is arranged to detect correlated data when thereis consistency between data received from the distance sensor, the railtranslation sensor and the rail torsion sensor to indicate presence of avehicle moving along the rail, based on the threshold values for each ofthe sensors.
 6. A vehicle detector unit as claim in claim 5, wherein theprocessor is arranged to detect correlated data for fast short vehiclesand slow long vehicles on the rail, and to detect uncorrelated data forwind-blown debris, dust, rain and the like.
 7. A vehicle detector unitas claimed in claim 1, wherein the processor is arranged to distinguishpresence of vehicles on adjacent tracks from presence of vehicles onsaid rail.
 8. A vehicle detector unit as claimed in claim 1, wherein thedistance sensor is in the form of an ultrasonic sensor.
 9. A vehicledetector unit as claimed in claim 1, wherein the rail translation sensoris in the form of an accelerometer.
 10. A vehicle detector unit asclaimed in claim 1, wherein the rail torsion sensor is in the form of agyroscopic sensor.
 11. A vehicle detector unit as claimed in claim 1,wherein the vehicle detector unit includes base for passing beneath saidrail, a first clamp which is fixed relative to the base for clamping oneside of the rail, and a second clamp which is selectively movablerelative to the base for clamping an opposite side of the rail.
 12. Avehicle detector unit as claimed in claim 11, wherein the second clampis selectively held in place relative to the base by operation of areleasable fastener.
 13. A vehicle detector system for detectingpresence of a vehicle moving along a rail relative to a work site, saidsystem including a pair of vehicle detector units at spaced locationsalong the rail, a first one of the vehicle detector units being locatedin one direction from the work site and a second one of the vehicledetector units being located in an opposite direction from the worksite, each of the vehicle detector units being a vehicle detector unitas claimed in claim 1, said system further including a site warning unitlocated at the work site, wherein the site warning unit is incommunication with the vehicle detector units, and the site warning unitoutputs audible and/or visual alerts in response to an alert signalreceived from either of the vehicle detector units.
 14. A vehicledetector system as claimed in claim 13, wherein the site warning unit isin communication with the vehicle detector units by way of radiocommunication.
 15. A method for detecting presence of a vehicle on arail, said method including the steps of: using a distance sensor forsensing a body of the vehicle, using a rail translation sensor forsensing translation of the rail, using a rail torsion sensor for sensingtorsion of the rail, and processing data received from the distancesensor, the rail translation sensor and the rail torsion sensor, wherebyan algorithm is applied to said data to determine whether to output analert signal. 16-18. (canceled)